When logging on to Linux,/etc/profile ,~ /. Execution process of files such as bash_profile

When you log on to Linux, the file execution process is as follows: when you first log on to Linux, start the/etc/profile file, and then start ~ /. Bash_profile ,~ /. Bash_login or ~ /. One of the profile files is executed in the following sequence :~ /. Bash_profile ,~ /. Bash_login ,~ /. Profile. If

The file execution process when logging on to Linux is as follows:

When logging on to Linux, start the/etc/profile file first, and then start ~ /. Bash_profile ,~ /. Bash_login or ~ /One of the. profile files,

The execution sequence is :~ /. Bash_profile ,~ /. Bash_login ,~ /. Profile.

If ~ /. If the bash_profile file exists, it is generally executed ~ /. Bashrc file.

Because in ~ The/. bash_profile file usually contains the following code:
If [-f ~ /. Bashrc]; then

../Bashrc

Fi

~ /. Bashrc usually has the following code:
If [-f/etc/bashrc]; then

./Bashrc

Fi

So ,~ /. Bashrc calls the/etc/bashrc file. Finally, when you exit the shell, ~ /. Bash_logout file.
The execution sequence is:/etc/profile-> (~ /. Bash_profile | ~ /. Bash_login | ~ /. Profile)-> ~ /. Bashrc->/etc/bashrc-> ~ /. Bash_logout
The scope of each file is described as follows:

(1)/etc/profile: This file sets the environment information for each user in the system. when the user logs on for the first time, this file is executed. and from/etc/profile. d Directory configuration file to collect shell settings.

(2)/etc/bashrc: execute this file for every user running bash shell. when bashshell is opened, the file is read.

(3)~ /. Bash_profile:Each user can use this file to input the shell Information dedicated to his own use. when a user logs on, this file is only executed once! By default, it sets some environment variables to execute the user's. bashrc file.

(4)~ /. Bashrc:This file contains bash information dedicated to your bashshell. This file is read when you log on and each time you open a new shell.

(5 )~ /. Bash_logout: execute this file every time you exit the system (exit bash shell). In addition, the variable (global) set in/etc/profile can act on any user, and ~ The variables (local) set in/. bashrc can only inherit the variables in/etc/profile. they are "parent-child" relationships.

(6 )~ /. Bash_profile is interactive and login to run bash ~ /. Bashrc is the interactive non-login mode that enters bash. Generally, the two settings are roughly the same, so the former usually calls the latter.

Use of environment variable setting files such as/etc/profile and/etc/environment

Add export LANG = zh_CN to/etc/profile, log out of the system, and log on again. The logon prompt is in English.

Delete exportLANG = zh_CN in/etc/profile, add LNAG = zh_CN to/etc/environment, log out of the system and log on again. The logon prompt displays Chinese characters.

When the user environment is established, the/etc/profile is always executed first and then the/etc/environment is read. Why is there a difference as described above?

Run/etc/environment first and then/etc/profile.

/Etc/environment is used to set the environment of the entire system, while/etc/profile is used to set the environment of all users. The former has nothing to do with the login user, and the latter has to do with the login user.
The execution of system applications may be unrelated to the user environment, but related to the system environment. Therefore, when you log on, you will see the prompt information, the display format of date and time information is related to the LANG in the system environment. the default is LANG = en_US. if the system environment LANG = zh_CN, the message is displayed in Chinese, otherwise, it is in English.

For SHELL initialization, run/etc/profile first and then read the file/etc/environment. for the whole system, run/etc/environment first. Is this true?

/Etc/enviroment -->/etc/profile --> $ HOME/. profile --> $ HOME/. env (if any)

/Etc/profile is the environment variable of all users

/Etc/enviroment is the system environment variable

The sequence of shell reading when logging on to the system should be
/Etc/profile->/etc/enviroment --> $ HOME/. profile --> $ HOME/. env
The reason should be the difference between the user environment and the system environment mentioned by jtw.

If the same variable has different values in the user environment (/etc/profile) and system environment (/etc/environment), the user environment should prevail.